A hierarchy of three strategies of analysis to investigate the determinants of fertility levels and changes in developing countries in general, and Latin American in particular, is proposed. The dimension along which the hierarchy is defined is the level of aggregation of the fertility conditionng factors, and the level of aggregation of the measures of fertility. Each strategy is designed to tap different sources of informaton: i) standardized birth rates and general fertility rates at the country level, originated in (corrected) vital statistics, ii) age-period specific fertility rates for population groups within regions and countries, originated by application of own children methods to censal data and iii) individual measures of reproductive performance derived from maternity histories collected in the World Fertility Survey. Introducing progressively more complex statistical models, each strategy is designed to quantify the effects on fertility of microlevel factors (affecting individual and groups in the same community and society) and macrolevel factors (affecting entire communities and societies). The theoretical model proposed will be tested on Latin American data.